In general, a laundry treatment apparatus is an apparatus for treating the laundry through processes, such as washing, rinse, dehydration and dry, in order to remove pollutants adhered on clothes, bedclothes and so on (hereinafter, referred to as “laundry”) by means of water, a detergent and mechanical action. The laundry treatment apparatus includes a washing machine for washing the laundry, a drying machine for drying wet laundry, a combination dry and washing machine for washing and drying the laundry, and so on.
The laundry treatment apparatus is equipped with a control unit for receiving a laundry treatment method from a user and automatically controlling the operation of the laundry treatment apparatus according to the treatment method. The control unit includes a manipulation unit for allowing a user to input a variety of commands, and a display unit for displaying an operating status of the apparatus to the outside.
Accordingly, a user can directly control the operation of the machine through the manipulation unit or can properly set a control program of the control unit. The manipulation unit includes a variety of manipulation switches. The manipulation switch can include a press switch, a slide switch, a rotary switch and so on according to a manipulation method. A representative rotary switch is a knob switch.
The knob switch includes a cylindrical knob rotatably disposed in the manipulation unit, and an encoder connected to the rotation center of the knob and configured to generate different control signals according to rotation angles of the knob.
The knob is rotatably disposed in a control panel forming the appearance of the control unit. The encoder is mounted in a board provided within the control unit, and has a rotation axis coupled to the knob. Space exists between the control panel and the board. Thus, the rotation axis of the encoder is lengthily projected toward the knob. A connecting shaft is lengthily projected toward the encoder in the rear of the knob and is then connected to the rotation axis.
In the knob switch of the conventional control unit, however, the rotation axis and the connecting shaft are lengthily formed and are connected to each other. Accordingly, there is a problem in that the connection structure of the encoder and the knob is very unstable. That is, problems arise because the connecting portion of the encoder and the knob is easily shaken and is easily broken by external shock, shaking, etc.
Accordingly, in recent knob switches, a thickness of each of the rotation axis and the connecting shaft is increased and structures, such as a reinforcement rib, are also added in order to reinforce the connecting portion of the encoder and the knob. Alternatively, an additional support member adhered closely to the outer circumferential surfaces of the rotation axis and the connecting shaft is added.
However, if the connecting portion of the rotation axis and the connecting shaft is reinforced as described above, there are problems in that the material cost increases and the fabrication of parts is difficult. Further, if the support member to support the rotation axis and the connecting shaft is provided, there is a problem in that upon rotation of the knob, frictional noise is generated due to the frictional action of the support member or a feeling of manipulation is greatly lowered.